Rear distributor chain up and down much more than 5 mm

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pierodn

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Hi.
the chain has too much play, more than 5 mm.
It is a Renold 42 L and comes new .
You know that it is impossible to tight.
The cam sprocket, intermediate gear and and cam chain, are all well in place.
The distributor sprocket is a stock 18 theet.
I can think that the problems can be only that the new chain is not good, what else?
Better to change with a new other one like Jwis?.
Thanks
Piero
 
I can remember that ones I worked on the mounting studs were "wasted" meaning they had a smaller diameter where the ignition housing fits.
this allowed the ignition housing to be adjusted slightly.
 
madass140 said:
I can remember that ones I worked on the mounting studs were "wasted" meaning they had a smaller diameter where the ignition housing fits.
this allowed the ignition housing to be adjusted slightly.
Click to expand...
Hi.
I understand, but if, the chain/sprocket is very close to the edge.
Piero
 
Rear distributor is only on a twin chain motor, commando 1968-1970(partial) 20M3 or prior Norton Heavy Twin 1948-1968.
most commando guys don't have a clue
The cam chain is one and a front chain tensioner has no effect on a rear chain...the rear chain is to the distributor or magneto on earlier NHT.

The chain may be worn out. I have 10 of these twin chain engines and I have not yet seen a set of sprockets worn out ..though I assume it is possible.
 
pierodn said:
madass140 said:
I can remember that ones I worked on the mounting studs were "wasted" meaning they had a smaller diameter where the ignition housing fits.
this allowed the ignition housing to be adjusted slightly.
Click to expand...
Hi.
I understand, but if, the chain/sprocket is very close to the edge.
Piero
Click to expand...

The studs are 5/16" OD (0.312") and waist down to 1/4" OD (0.250"). That allows an adjustment of 1/32" (0.031"). That is not much, but the chain slack will take up significantly. Normally, the chain and sprocket are very close to the timing case wall.

Piero: Check that your studs are "waist-ed". I have seen some that were not.

Slick
 
texasSlick said:
pierodn said:
madass140 said:
I can remember that ones I worked on the mounting studs were "wasted" meaning they had a smaller diameter where the ignition housing fits.
this allowed the ignition housing to be adjusted slightly.
Click to expand...
Hi.
I understand, but if, the chain/sprocket is very close to the edge.
Piero
Click to expand...

The studs are 5/16" OD (0.312") and waist down to 1/4" OD (0.250"). That allows an adjustment of 1/32" (0.031"). That is not much, but the chain slack will take up significantly. Normally, the chain and sprocket are very close to the timing case wall.

Piero: Check that your studs are "waist-ed". I have seen some that were not.

Slick
Click to expand...
Hi.
You had right.
The two studs screwed into the case was not wasted.
I have replayed with two wasted and now with new clearance the distributor body mooves a little bit that permits to the chain to go rear.
Now the chain is well tight.
Tanks to all for helping me.
Piero
 
Piero:

Do not run the chain too tight ..... 3/16" (4.75 mm) up/down movement in the chain is the specification. Too tight will wear the bearing in the distributor. Also, the timing advance mechanism may "stick" in the advanced position.

Slick
 
I have shares in Renold but I will not sell the new brand.

Look for the stamp Renold UK or Renold England.

This good
 
texasSlick said:
Piero:

Also, the timing advance mechanism may "stick" in the advanced position.

Slick
Click to expand...

:?:
How does the chain tension affect the aa unit INSIDE the distributor?
It is not like a mag
 
dynodave said:
texasSlick said:
Piero:

Also, the timing advance mechanism may "stick" in the advanced position.

Slick
Click to expand...

:?:
How does the chain tension affect the aa unit INSIDE the distributor?
It is not like a mag
Click to expand...

The chain tension is known to cause sticking in the Lucas magneto ATD .... reference Norton manuals. I used the word may as a precaution. Perhaps it is inappropriate to make the extension from external to internal, but if it occurs in one case, it is well to be wary in the other. Regardless, too tight is inappropriate.

Slick
 
My question was a bit rhetorical, and I will then state, chain tension has NO effect on an internal distributors AA unit.
 
texasSlick said:
Piero:

Do not run the chain too tight ..... 3/16" (4.75 mm) up/down movement in the chain is the specification. Too tight will wear the bearing in the distributor. Also, the timing advance mechanism may "stick" in the advanced position.

Slick
Click to expand...

Hi Slick,
thank you.
About 4 mm up and down it works.
Piero
 
Hi,
about "chain up and down" what is the correct cam chain movement?
Do you like thevcam chain tensioner with the rubber?
thank you.
Piero
 
pierodn said:
Hi,
about "chain up and down" what is the correct cam chain movement?
Do you like thevcam chain tensioner with the rubber?
thank you.
Piero
Click to expand...

Cam chain has same specification as distributor/magneto chain .... 3/16 inch or about 4.75 mm.

Slick
 
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